Pregnancy Week by Week

Find pregnancy week by week info on baby’s development, pregnancy symptoms week-by-week, and weekly tasks from our Parenthoodbliss articles.

General Guidance On Pregnancy Week By Week

Weeks 1-2

Conception is also known as fertilization usually happens about 2 weeks after the starting of the last menstrual period (also known as LMP). Conception is when the man’s sperm fertilizes the woman’s egg. The conception will happen in one of the fallopian tubes. These are the tubes that are between the ovaries and the uterus (womb).

It is likely for you to not know the exact date you get pregnant. This is why medical health care providers use the LMP to find out how far you are in pregnancy.

Weeks 3-4

The fertilized egg will move through the fallopian tubes towards the uterus and attach to the lining of the uterus known as implantation. Once it is implanted, it will begin to grow, and the placenta forms. The placenta will grow in the uterus and supply the baby with oxygen and food through the umbilical cord.

Weeks 5-7

The baby’s neural tube forms. This neural tube will become the baby’s spinal cord, brain, and backbone. Tiny buds will start appearing that become the baby’s arms and legs. The baby’s heart and lungs will develop, and even the heart starts to beat.

Weeks 8-10

The baby’s bones will start to form and they are still soft. They harden as the baby develops along in your pregnancy. They will now have eyelids, but they remain shut. The baby’s genitals also begin to form.

Weeks 11-14

Fingers and toes will continue to develop and the baby’s nails grow. You will be able to hear the baby’s heartbeat at the prenatal care checkup.

Weeks 15-20

This is the start of the second trimester! The baby is growing fast. Their organs are completely formed and continue developing. On ultrasound, it can look like the baby’s breathing and swallowing.

Weeks 21-24

The eyelids, ears, and upper lip have developed by now. They can hear you! You can talk or sing to them as much as you feel like. The baby now is about 5 inches long and weighs almost 5 ounces.

Weeks 25-27

The baby’s nails grow toward the ends of their fingers. During this time the baby is about 10 inches long and will be 1 pound of weight. The fingers and toes of the baby are fully formed, which includes her finger and toe prints. The baby can now swallow and from time to time, they may even hiccup! You may feel gestures as regular, jerky movements.

Weeks 28-30

The baby’s muscles will continue to grow. They may start to have hair on their head. The lungs are fully formed but they are not ready to breathe outside of the womb yet. They will now be about 12 inches long and their weight will be little more than 1 pound.

Weeks 31-35

The baby will have eyelashes and he/she can open and close their eyes. The baby is about 14 inches long and will weigh about 2½ pounds. The brain of the baby develops and grows quickly. Their brain can now help control their body heat.

Weeks 36-39

The vernix, which is the waxy, greasy coating that will protect the baby’s skin in your womb, starts getting thicker. Most babies are likely to move into a head-down position for getting ready for labor and birth. This may happen this week or in the next few weeks.

Week 40

Congratulations on 40 weeks! The baby is ready to be born. Your baby has time to develop fully and is ready to finally meet you face to face. Call the provider whenever you think you are in labor. The baby will be about 18 to 20 inches long and will weigh about 6 to 9 pounds.

FAQs

1. What week is the most critical in pregnancy?

Your fetus is most vulnerable during your first 12 weeks of pregnancy. During this time, the major organs of the baby are forming and might get damaged if not taken care of.

2. Which week is safe for delivery?

If the pregnancy is healthy, it is best to stay pregnant for about 39 weeks and then wait for labor to begin naturally.

3. What happens during the 40th week of pregnancy?

The baby is ready to be born. Your baby has time to develop fully and is ready to finally meet you face to face. Call the provider whenever you think you are in labor. The baby will be about 18 to 20 inches long and will weigh about 6 to 9 pounds.